﻿// Copyright 2015-2023 Serilog Contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Serilog.Sinks.Http.BatchFormatters;

/// <summary>
/// Formatter serializing batches of log events into a JSON array.
/// <para />
/// Example:
/// [
///   { event n },
///   { event n+1 }
/// ]
/// </summary>
public class ArrayBatchFormatter : IBatchFormatter
{
    /// <inheritdoc />
    public void Format(IEnumerable<string> logEvents, TextWriter output)
    {
        if (logEvents == null) throw new ArgumentNullException(nameof(logEvents));
        if (output == null) throw new ArgumentNullException(nameof(output));

        // Abort if sequence of log events is empty
        if (!logEvents.Any())
        {
            return;
        }

        output.Write("[");

        var delimStart = string.Empty;

        foreach (var logEvent in logEvents)
        {
            if (string.IsNullOrWhiteSpace(logEvent))
            {
                continue;
            }

            output.Write(delimStart);
            output.Write(logEvent);
            delimStart = ",";
        }

        output.Write("]");
    }
}